This relates to a method and apparatus for communication using time-reversal techniques, and particularly to the use of such techniques in systems having multiple transmitters and/or receivers.
In communications systems having multiple transmitters and/or receivers, such as Multiple-Input/Multiple-Output (“MIMO”) systems, the power of a signal that reaches a particular intended receiver will have been attenuated as the signal propagates throughout the system. This may give rise to other performance issues such as increased inter-symbol interference (“ISI”).
Use of time-reversal communications techniques, originally developed in acoustic systems, but applicable also to electromagnetic (e.g., radio-frequency) communications, may address some of these issues, but may also affect the power spectral density (“PSD”) in a way that may give rise to spectral mask violations.